A compaction machine is a kind of construction machinery used to impact and compact construction materials or foundations. The compaction machine is widely used in construction operations of industrial and civil buildings, warehouses, yards, docks, airports, foundations of roads and railways, artificial islands, and so on. A lifting mechanism is an important component of a compaction machine. After the lifting mechanism lifts a compaction hammer of the compaction machine to certain height, and releases the compaction hammer to let the compaction hammer fall freely. The free fall of the compaction hammer (a) applies a strong impact force and vibrations to a soil or other construction material surface or a foundation, (b) compacts the soil or other construction materials, (c) decreases compressibility of the soil or other construction materials, (d) improves evenness of the surface of the soil or other construction materials, and (e) reduces future differential settlement.
The lifting mechanism of a compaction machine is generally a winch-type lifting mechanism. The winch-type lifting mechanism includes structures such as a motor (an electric motor or a hydraulic motor), a speed reducer, a clutch, a spool, and a brake. The winch-type lifting mechanism needs to have high braking capacity, and has strict requirements on the clutch regarding shock resistance, friction, and resistance to high temperatures. These requirements greatly increase production and manufacturing costs. Further, the control system of the winch-type lifting mechanism is very complicated, and very difficult to manufacture and maintain, and very difficult for operators to adjust and maintain on a daily basis. As the compaction machine is increasingly frequently used, a ramming process of the compaction hammer frequently impacts the winch-type lifting mechanism. These impacts will likely cause it to fail, cause severe damages to the components, such as the motor, the clutch, and the brake due to fatigue, and increase the maintenance costs of the compaction machine.
Additionally, the compaction machine works in a special environment. During ramming of the compaction hammer, the spool rotates at a high speed of 10 r/s. When a steel wire rope is released from the spool, a certain inclination angle may be formed between the steel wire rope and the axis of the spool. It may cause the spool to shake. In certain extreme cases, such shake may cause internal oil leakage, and reduce reliability and safety during use.
As the compaction machine is increasingly required on construction sites, requirements on performance of the compaction machine become higher and stricter. In view of the defects of existing winch-type lifting mechanism having high production, manufacturing, and maintenance costs, it is desirable to have a lifting mechanism of a compaction machine with low production, manufacturing, and maintenance costs, high reliability, and small in size, to meet increasing demands for the compaction machine from users.
Therefore, heretofore unaddressed needs exist in the art to address the aforementioned deficiencies and inadequacies.